I have typically employed the following philosophy for line stop loads (limit stops, bumpers, stoppers, ...):

"The design load shall be the greater of the net load or 25% of the maximum load from either side. If one side of the bumper can be isolated/ambient, the design load shall be the higher one sided load."

Zero load shall not be given to Civil. I have seen some folks use 20% or 30% versus the 25% stated.